RE: accessing the records in a history file -- MIDRANGE-L

Title: RE: accessing the records in a history file

Your statement is a little misleading. Encoded Vector Indexes can only be created in SQL. However, their access path can be used by OPNQRYF also.

Dave

-----Original Message-----
From: Al Barsa, Jr. [mailto:barsa2@ibm.net]
Sent: Thursday, December 21, 2000 2:45 PM
To: MIDRANGE-L@midrange.com
Subject: RE: accessing the records in a history file

At 07:18 PM 12/21/00 +0000, you wrote:
>What is an Encoded Vector Index? This is a new term for me.

It's a new type of index, added in a recent release (I think 4.2 otherwise
4.4), where an index with select omit criteria is created in memory with
one bit (on or off) signifying that a record is to be selected or
omitted. As you typically can get that much memory available, this is
tantamount to putting the select omit portion of the index totally into
memory. If you use SQL, and if you can use this feature, you can drop the
query portion of time by up to 95%. (Available only in SQL, not OPNQRYF or
DDS, because someone in Rochester doesn't give a @#$% about existing
users.) An AS/400 first!

>_______________________
>Booth Martin
>Booth@MartinVT.com
>http://www.MartinVT.com
>_______________________
>
>
>
>
>"Leland, David" <dleland@Harter.com>
>Sent by: owner-midrange-l@midrange.com
>12/21/2000 12:14 PM
>Please respond to MIDRANGE-L
>
>
>         To:     "'MIDRANGE-L@midrange.com'" <MIDRANGE-L@midrange.com>
>         cc:
>         Subject:        RE: accessing the records in a history file
>Encoded Vector Indexes are great for enhancing the performance of adhoc
>queries against large files. Not sure if this fits your situation
>exactly, but I would do one over DATE, one over TIME and one over Customer
>ID. Obviously, if you always know what criteria and sorting you are going
>to do, a regular logical would work just as well. But if you have this
>large of a file, you need to have some permanent access paths over it that
>will make accessing the records you want faster. This will help
>regardless of whether you use OPNQRYF or SQL.
>Dave
>-----Original Message-----
>From: booth@martinvt.com [mailto:booth@martinvt.com]
>Sent: Thursday, December 21, 2000 11:44 AM
>To: midrange-l@midrange.com
>Subject: accessing the records in a history file
>
>I'd like some insight from folks on this scenario: There is a history
>file of records dating from 1994. Records are added each day and now
>there are 3.6 million records in the file. The odds of anyone going back
>to look up something in 1994 are slim but management won't purge any
>records. Obviously the newest records are at the end of the file. All of
>
>the logicals have the customer ID number as the first key. One logical has
>
>a key of the customer ID and then date and time.
>Each business day there is at least one and sometimes five or more reports
>
>written for all activity during some recent time period (a workshift, a
>day, a week, whatever).
>This process is becoming a performance pig; additionally there is a need
>for more function.   What sorts of suggestions do you people see as
>possible enhancements to this? SQLRPGLE? OPNQRYF? a new Logical on date
>and time alone? #GSORT?
>Any suggestions are appreciated. thanks in advance.
>
>_______________________
>Booth Martin
>Booth@MartinVT.com
>http://www.MartinVT.com
>_______________________
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Al Barsa, Jr. - Account for Midrange-L
Barsa Consulting Group, LLC.
400 > 390

Phone: 914-251-1234
Fax: 914-251-9406
http://www.barsaconsulting.com
http://www.taatool.com

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